1. Field of the Invention
The invention relates to the conversion of olefins to liquid motor fuels. More particularly, it relates to the conversion of such olefins to hydrocarbons boiling in the gasoline and jet fuel+diesel oil boiling range.
2. Description of the Prior Art
It is well known in the art that small olefins can be converted to gasoline range hydrocarbons. For this purpose, a molecular sieve catalyst material, such as an acidic crystalline aluminosilicate, for example ZSM-5, has been employed. When it is desired to convert such small olefins specifically to hydrocarbons boiling in the jet fuel+diesel oil boiling range, however, such an approach has not been found suitable since the use of ZSM-5 is found to experience an effective limitation at the C.sub.10 carbon number without recycle. The use of ZSM-5 for methanol and syngas conversion was likewise found to experience this limitation. Those skilled in the art will appreciate that the end point of gasoline is about 420.degree. F., while the diesel oil end point is about 700.degree. F. Said 420.degree.-700.degree. F. hydrocarbon material comprises molecules with more carbon atoms than C.sub.10 hydrocarbons up to about C.sub.22 material. Hydrocarbon material in the C.sub.22 -C.sub.28 range generally comprises heavy distillate material, with material above C.sub.28 generally comprising wax.
While the conversion of small olefins using ZSM-5 catalyst was thus initially limited to production of gasoline range material, it has subsequently been found that, by recycling the gasoline range product back over the catalyst along with fresh feed, the product obtained can be extended into the diesel oil range. While such extension of the product range is desirable, the need for employing a recycle feature, and the costs associated with such recycle, serve to render this approach not entirely satisfactory from an overall technical-economic viewpoint. Accordingly, it is desired in the art that a more direct process be found for converting small olefins to liquid hydrocarbon fuels boiling in the jet fuel and diesel oil range, i.e. fuels containing hydrocarbons comprising C.sub.10 up to C.sub.22 material.
It is an object of the invention, therefore, to provide an improved process for the conversion of olefins to liquid hydrocarbon motor fuels.
It is another object of the invention to provide a catalyst capable of enhancing the conversion of olefins to such liquid fuels.
It is further object of the invention to provide an improved process and catalyst composition for producing liquid motor fuels boiling in the gasoline and jet fuel+diesel oil boiling range.
With these and other objects in mind, the invention is hereinafter described in detail, the novel features thereof being particularly pointed out in the appended claims.